Cardiac Electro-Physiological (EP) study procedures involve sensing and recording EP signals from a patient's heart, e.g., using a cardiac catheter. In some EP study procedures, the patient's heart is paced by applying pacing signals. EP study is sometimes carried out in conjunction with an ablation procedure, in which ablation signals are applied to a certain region on the heart's surface.
Several methods and systems for coordinating EP signals, pacing signals and/or ablation signals during such procedures are known in the art. For example, PCT International Publication WO 1997/06729, whose disclosure is incorporated herein by reference, describes an EP system that includes an amplification system, an ablation machine, a filter box, a display monitor and a chart recorder. The amplification system receives endocardial signals from an ablation catheter during both an EP study and an ablation procedure. The amplification system, ablation machine and ablation catheter are interconnected with the filter box such that the endocardial signals and the high energy ablation signal pass therethrough and are filtered thereby.
PCT International Publication WO 1994/10904, whose disclosure is incorporated herein by reference, describes an ablation catheter, which has an ablation electrode at its distal end coupled to an ablation power source through low-impedance coupling. The ablation electrode also functions as a sensing electrode for monitoring an endocardial signal and preferably also tissue impedance during an ablation procedure. The ablation electrode is coupled to an electrode monitor through high-impedance coupling. A timing element operates a plurality of switches to selectively isolate, dampen or interconnect various signal paths during plural repetitive non-overlapping ablation and quiescent intervals. RF energy is delivered to the ablation site during the ablation intervals. The local endocardial signal is measured during the quiescent intervals.
U.S. Patent Application Publication 2008/0281312, whose disclosure is incorporated herein by reference, describes an ablation therapy system, which includes a Multi-Channel RF Ablation Generator, an ECG interface, an assembly of at least three ablation catheters and an ECG interface operably coupling and interfacing the catheters to both an ECG unit and the RF Ablation Generator.